In recent years, environmental issues such as global warming and the like that are attributed to increases in carbon dioxide have become serious. As a result, non-silicon solar cells have gained attention as solar cells that have little environmental impact and that also allow for reduced manufacturing costs; and research and development of such is moving forward.
Among non-silicon solar cells, the dye-sensitized solar cell developed by Graetzel et al. in Switzerland has attracted attention as a new type of solar cell. As a solar cell using organic materials, these solar cells have advantages such as high photoelectric conversion efficiency and lower manufacturing costs than silicon solar cells.
However, dye-sensitized solar cells are electrochemical cells, and therefore use organic electrolytic solutions and/or ionic liquids as electrolytes. In cases where organic electrolytic solutions are used, there is a problem in that electrical efficiency decreases due to volatilization and depletion during long-term use. Additionally, in cases where ionic liquids are used, while volatilization and depletion that occur during long-term use can be prevented, there are durability problems such as structural degradation caused by liquid leakage.
Therefore, research is being conducted regarding converting the electrolyte from a liquid to a gel or solid for the purpose of preventing the volatilization and liquid leakage of the electrolytic solution and ensuring the long-term stability and durability of the solar cell.
For example, Patent Document 1 describes an electrolyte for a photoelectric conversion element comprising (i) a lamellar clay mineral and/or an organically modified lamellar clay mineral and (ii) an ionic liquid (claim 1).